Elastic members for fitting the trunk of a wearer are known to be provided in addition to elastic members for the legs and those for the waist in order to fit disposable underpants or a disposable diaper to a wearer (for example, Japanese Unexamined Patent Publication No. 4-166150).
The disposable underpants and the like as above have an effect of a comfortable wearing feeling due to high fittability since a clearance is unlikely to be created between the wearer and the absorbent member particularly by elastic forces of the elastic members for fitting the trunk.
However, in the case of using a highly flexible thin absorbent member such as an absorbent member of a low Metsuke having a relatively small amount of pulp fibers or an absorbent member in the form of a thin sheet not using pulp fibers, there have been cases where widthwise shrinking forces by the elastic members for fitting the trunk and longitudinal shrinking forces by the elastic members for the legs act on the absorbent member to thereby twist the absorbent member. Metsuke is weight of fiber per unit area. If the absorbent member is twisted, a clearance is likely to be created between the wearer and the absorbent member. Such a clearance makes it difficult to prevent a lateral leak of urine and the like and reduces a fittability, whereby a comfortable wearing feeling cannot be obtained.
In view of the problems residing in the prior art, an object of the present invention is to provide disposable underpants which can prevent a lateral leak of urine and the like, has a high fittability and provides a comfort wearing feeling even if a highly flexible thin absorbent member is used.